Method for Obtaining Diagnostics and Control of the Pumping Process of Rod Pumped Oil and Gas Wells and Devices for the Method Execution

ABSTRACT

Devices and methods for obtaining diagnostics and control of the pumping process of rod pumped oil or gas wells are described. The diagnostics and control are implemented by means of the well simulation unit where surface load values are gathered through utilization of a load cell mounted on the carrier bar and attaching to the top of the polished rod and surface position values are gathered through the use of a position sensor mounted on the polish rod. Subsequently, an animation representing the entire pumping system is displayed instantaneously either on local display or by utilizing a HMI or a portable laptop, computer or other device connected to SCADA system. Changes of well conditions and pumping system conditions are displayed real time utilizing a direct simulation.

TECHNICAL FIELD

The invention is related to the method for obtaining diagnostics and control of the pumping process of rod pumped oil and gas wells by using a well simulation and control unit while the unit's load and position sensors are mounted on the polished rod of the surface pump and the gathered data are processed real time utilizing programmable controller and transformed into output animation depicting behaviour and loading of the entire pumping system.

TECHNOLOGICAL BACKGROUND

Much study and many devices have been utilized to attempt to match pumping system run times to reservoir inflows in an effort to eliminate fluid pound. Fluid pound occurs when the subsurface positive displacement pump no longer fills with liquid because the reservoir has inadequate inflows to fill the casing. Throttling the carburettor of gas powered combustion engines was one of the first methods utilized. With the advent of electric motors, timers where utilized as a means to turn on and off pumping units in an effort to control severe over displacement and avoid fluid pound. The industry standard has become the utilization of the modern pump-off controller. The most popular of these devices involve the creation of a surface or down hole dynamometer card. U.S. Pat. No. 3,306,210 describes one such method. The surface dynamometer card is merely a plot of the surface load and position of the polished rod. As the well pumps off, the pump load decreases due to incomplete pump fill. The result is a diminished load area on the surface dynamometer card. A set point of some type or another type of area loss is measured and the well is shut off for a predetermined downtime. During downtime the reservoir will replenish the casing. After downtime the well is restarted and the process repeated. U.S. Pat. No. 3,951,209 described a method to similar to U.S. Pat. No. 3,306,201 that measures area inside the surface dynamometer card. U.S. Pat. No. 4,583,915 describes a device that measures the area outside of the surface dynamometer card. U.S. Pat. No. 3,343,409 and U.S. Pat. No. 5,252,031, describe a procedure whereby the surface load and position is utilized to calculate a plot of down hole load and position most times referred to as the down hole dynamometer card. This method is used to detect various conditions and is utilized to control for pump-off.

The short comings of the aforementioned prior art are related to the difficulty in understanding and interpreting the surface and down hole dynamometer cards. Many conditions exist that affect the shape and reliability of these devices that solely depend on dynamometer cards. One almost need be a trained dynamometer analyst to insure that these devices are setup properly and correctly interpreted because the created dynamometric card is at least one stroke behind the actual stroke of the pump. This delay is detrimental to the instant decision making that safeguards smoothness of the whole pumping system operation. Utilization of a direct simulation of the precise conditions of the well will aid the operator to quickly understand, interpret, and interface with the device, in addition to easily recognizing the pump-off. Obtaining real time well diagnostics and displaying the pumping system loads will alert the operator and will be programmed to shutdown when pumping system overloading occurs.

SUBJECT MATTER OF THE INVENTION

Mentioned inadequacies are in fact removed by the method for obtaining diagnostics and control of the pumping process of rod pumped oil or gas wells characterized by the fact that the diagnostics and control are implemented by means of the well simulation unit so that surface load values are gathered through utilization of a load cell mounted on the carrier bar and attaching to the top of the polished rod and surface position values are gathered through the use of a position sensor mounted on the polish rod and an inclinometer mounted on the pumping unit, or position sensors mounted to trigger during cycling of the pumping unit, further also estimated or indirectly measured position and load, while the data obtained are wirelessly transmitted to the well simulation unit. Subsequently, animation representing the entire pumping system is displayed instantaneously either on local display or by utilizing a HMI or a portable laptop, or other device connected to SCADA system, and also changes of well conditions and pumping system conditions are displayed real time utilizing a direct simulation.

The diagnostics and control of the rod pump are implemented by means of the well simulation unit in those cases when a computer-generated two- and three-dimensional simulation or animation is used on the well site where position and load data are transmitted wirelessly from the end device, based on real time calculations of the pump function simulation where a rod string and the simulation of pump and the surface pumping unit are displayed on two- or three-dimensional graphical display, HMI, or laptop, computer or other device connected to SCADA system.

The diagnostics and control of the rod pump are implemented by means of the well simulation unit where diagnostic data and load values are displayed real time on a graphical display, HMI, or laptop, computer or other device connected to SCADA system; further the method for detection and control of pump-off or pump-fillage on a rod pumped well and the method for controlling the speed of a variable speed drive or variable frequency drive on the rod pump, and the method for monitoring and controlling a rod pumped well where the fluid level is displayed with casing and tubing, in all previous cases, by a computer-generated two- or three-dimensional simulation displayed on a graphical display, HMI, or laptop, computer or other device connected to SCADA system.

Devices for the method execution consists of the pumping unit with motor connected with a subsurface pump and a rod string, characterized by the fact that it is equipped with a well simulation and control unit comprising a programmable controller and a common casing, in which is integrated/combined load cell with a position sensor and a microcontroller, digital interface module, voltage transducer and the battery while the casing is wirelessly and/or via the cable connected with the programmable controller, while load cell and position sensor can be installed separated and connected to programmable controller wirelessly and/or via analog cable and for via digital cable.

Alternative device is characterized by well simulation and control unit consisting of programmable controller directly connected to the motor of pumping unit via cable.

In addition to monitoring the contents of the subsurface pump and shutting down to prevent fluid pound, a live and dynamic presentation of entire system will be displayed. The fluid level of the well, the pump intake pressure, pump leakage, subsurface pump and pump system diagnostics, as well as gas, oil, and water production will all be calculated and represented on the live display.

Variable speed or variable frequency drives are commonly utilized as method to speed up or slow down a well as an alternative to shutting down, going through downtime and restarting. This invention will interface and control all available drive mechanisms available in the industry today and the real time simulator will control via speed up or slow down in addition to traditional start and stop.

The advantages of the present invention over prior art is the practical easy to understand nature of the invention, and the fact that it is presented real-time. Recent prior art has always utilized dynamometer cards for control and monitoring of the pumping system. The pump system simulator utilizes state of the art electronic processors and graphics, which allows the operator to instantly recognize pump-off and changing well conditions. Most prior art represents a dynamometer card that is at least one stroke behind the actual stroke. This delay is detrimental to the instant decision making that the new invention allows. Industry operators are trained to understand the pumping system as they view it on a daily basis including the pumping unit, rods, prime mover, and subsurface pump. Surface and down hole dynamometer cards where first utilized in the industry in 1937. Interpretation of dynamometer cards is an ancient art which requires specialized training and years of experience. The animation represented by the new invention will require no specialized training and only a basic understanding of the pumping system. Dynamometer cards are presented along with the real time simulation for viewing purposes by those that are skilled in the art and desire to view such plots.

In broad embodiment, the invention is a rod pumping system controller that will be located at the well-site of a rod pumped well. In multi well fields it is possible to have a controller on each and every rod pumped well. These controllers can operate as stand alone devices or can be connected to a central computer via radio, satellite or some means of remote communication. Remote access allows the ability to monitor and interrogate the controllers without having to travel to the well site. The controllers can be interrogated at the well site by utilizing a local keypad and display, HMI device, or by utilizing a laptop computer. The invention will utilize the most current state of the art electronics to insure speed, reliability, and user friendliness. The real time display of the entire rod pumping system with complete diagnostics will allow the field operators a quick overview of the health of the pumping system. The user friendliness of the invention will allow the operators to quickly access the system and will reduce the amount of man hours spent attempting to interpret the overall state of the system.

While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiment, method, and examples herein. The invention should therefore not be limited by the above described embodiment, method, and examples, but by all embodiments and methods within the scope and spirit of the invention.

REVIEW OF FIGURES IN DRAWINGS

FIG. 1 represents a diagram of the well simulation and control unit during a wireless transmission.

FIG. 2 represents overall flow diagram of the method for obtaining diagnostics and control of the pumping process of rod pumped oil and gas wells.

FIG. 3 represents a diagram of the well simulation and control unit during a digital cable connection.

FIG. 4 represents a diagram of the well simulation and control unit during an analogue cable connection.

FIG. 5 represents a diagram of the well simulation and control unit during a sensorless configuration.

FIG. 6 represents a diagram of the well simulation and control unit during separately installed load cell and position sensor with analog and/or digital cable connection.

FIG. 7 represents a diagram of the well simulation and control unit during separately installed load cell and position sensor with wireless connection.

EXAMPLES OF THE INVENTION IMPLEMENTATION Implementation Example No. 1

The flow diagram according to FIG. 2 represents an overall influence of the well simulation and control unit on the whole pumping process. Individual blocks are labelled with Arabic numerals with the following explanatory comments:

-   -   (A) position sensor—point of measurement of the position value     -   (B) load cell—point of measurement of the surface load     -   (C) auxiliary sensors (not necessarily used)     -   (D) estimated or indirectly measured position and load     -   (E) data obtaining and saving into the memory of programmable         controller (R)     -   (F) detection of beginning and termination of the cycle. Check         of setpoints against actual values (P) saved in the memory of         programmable controller (R).     -   (G) emergency shutdown based on setpoints?     -   (H) if (G)“yes”—a command to stop the well/pump     -   (I) is the alarm counter exceeded?     -   (J) if (I) “yes”—waiting for the manual command from the SCADA         system (supervisory control and data acquisition) connected to         the programmable controller or from the operator using the         graphical user interface (S)     -   (K) a command start the well/pump; (E) obtain data and save them         into the memory     -   (L) if (I) “no”—leave the well stopped until external command         received from SCADA system or graphical user interface—(K) a         command start the well/pump; (E) obtain data and save them into         the memory     -   (M) if (G) “no” modelling the change of well state and depiction         of it together with surface and downhole dynagraph. Saving the         well state into memory of the programmable controller (R) as         data with a time marking (O).     -   (N) calculations of pump fillage, production and pump intake         pressure in well simulator. Saving the data into the memory of         the programmable controller (R) as data with a time marking (O).     -   (Q) Shutdown on the basis of the well simulator parameters?

Implementation Example No. 2

The well simulation and control unit 1 (FIG. 1) consists of the programmable controller 2 and a common casing 3 in which is integrated/combined load cell 4 with a position sensor 5 and a microcontroller 6 digital interface module 7 voltage transducer 8 and the battery 9. The battery 9 is connected to the voltage transducer 8 that changes voltage into the correct excitation voltage for the position sensor 5 and the load cell 4. The microcontroller 6 amplifies analogue signal from the sensors 4 and 5, converts it, and sends it wirelessly through the wireless digital interface module 7 with an aerial to the programmable controller 2. The programmable controller 2 receives the digital signal by means of its own wireless interface module.

Implementation Example No. 3

The well simulation and control unit 1 (FIG. 3) consists of the programmable controller 2 and a common casing 3 in which is integrated/combined load cell 4 with a position sensor 5 and a microcontroller 6 digital interface module 7, voltage transducer 8. Energy from the power supply is delivered through the cable into the casing 3 where the voltage transducer 8 changes voltage into the correct excitation voltage for the position sensor 5 and the load cell 4. The microcontroller 6 amplifies analogue signal from the sensors 4 and 5, converts it, and sends it using the digital interface module 7 via the cable 10 to the programmable controller 2.

Implementation Example No. 4

The well simulation and control unit 1 (FIG. 4) consists of the programmable controller 2 and a common casing 3 in which is integrated/combined load cell 4 with a position sensor 5 and voltage transducer 8. Energy from the power supply is delivered into the casing 3 where the voltage transducer 8 changes voltage into the correct excitation voltage for the position sensor 5 and the load cell 4. The programmable controller 2 receives analogue signal from the sensors 4 and 5 via the cable 10.

Implementation Example No. 5

The well simulation and control unit 1 (FIG. 5) consists of the programmable controller 2. 3-phase voltage of pumping unit motor 11 is connected by wires 12 to inputs of the programmable controller 2 which estimates load and position using motor voltage and current.

Implementation Example No. 6

The well simulation and control unit 1 (FIG. 6) consists of the programmable controller 2 connected to load cell 4 and position sensor 5. Programmable controller 2 receives signal from load cell 4 and position sensor 5 via analog and/or via digital cables 10.

Implementation Example No. 7

The well simulation and control unit 1 (FIG. 7) consists of the programmable controller 2 connected to load cell 4 and position sensor 5. Programmable controller 2 receives signal from load cell 4 and position sensor 5 wirelessly.

Examples Nos. 2 to 7 mention possible alternatives of integration for the programming and control of the whole technological pumping process of oil and gas wells with regard to local conditions of the place of application.

INDUSTRIAL APPLICABILITY

The invention relates to extractive industry, mainly crude-oil and gas production, where the device for monitoring and controlling a rod pumped well is placed directly on the oil well system. 

1-5. (canceled)
 6. A method for obtaining diagnostics and control f the pumping process of rod pumped oil or gas wells comprising: gathering surface load values for the polished rod; gathering surface position values for the polished rod; using a well simulation unit to plot the surface load values against the position of the polished rod; and displaying an animation representing the entire pumping system showing changes in well conditions and pumping system conditions in real time.
 7. The method of claim 6 wherein the surface load values are gathered through the use of a load cell mounted on a carrier bar attached to a top of a polished rod.
 8. The method of claim 6 wherein the surface position values are gathered through the use of a position sensor mounted to the top surface of the polished rod and an inclinometer mounted on a pumping unit.
 9. The method of claim 6 where the gathering is done by one of: wired or wireless transmission.
 10. The method of claim 6 wherein the animation representing the entire pumping system is displayed instantaneously on one of a local display; an HMI; a portable laptop; a remote computer; or a device connected to SCADA system.
 11. The method of claim 6 further comprising detecting pump-off conditions on a rod pumped well.
 12. The method of claim 6 further comprising controlling the speed of a drive on the rod pump.
 13. A controller for use with a rod pumped oil or gas well comprising: a load sensor gathering surface load values for the polished rod; at least one position sensor gathering surface position values for the polished rod; and a well simulation unit to plot the surface load values against the position of the polished rod based on data received from the load sensor and the at least one position sensor; wherein the well simulation unit generates an animation representing the entire pumping system showing changes in well conditions and pumping system conditions in real time.
 14. The controller of claim 13 wherein the load sensor includes a load cell mounted on a carrier bar attached to a top of a polished rod.
 15. The controller of claim 13 wherein the at least one position sensor includes a position sensor mounted to the top surface of the polished rod and an inclinometer mounted on a pumping unit.
 16. The controller of claim 13 where the load sensor and the at least one position sensor transmit data by one of wired or wireless transmission.
 17. The controller of claim 13 wherein the animation representing the entire pumping system is displayed instantaneously on one of: a local display; an HMI; a portable laptop; a remote computer; or a device connected to SCADA system.
 18. The controller of claim 13 wherein the controller uses the animation to detect pump-off conditions on a rod pumped well.
 19. The controller of claim 13 wherein the controller uses the animation to control the speed of a drive on the rod pump.
 20. A device for controlling a rod pumped oil or gas well comprising: a programmable controller; an integrated combined load cell measuring a load on a rod in the rod pumped well; a position sensor measuring the position of the rod; a microcontroller, wherein the integrated combined load cell, the position send and the microcontroller are in a common casing and communicate with the programmable controller; a digital interface module; and a well simulation unit in the programmable controller to plot the surface load values against the position of the polished rod based on data received from the load sensor and the at least one position sensor, wherein the well simulation unit generates an animation representing the entire pumping system showing changes in well conditions and pumping system conditions in real time.
 21. The device of claim 20 wherein the animation representing the entire pumping system is displayed instantaneously on one of: a local display; an HMI; a portable laptop; a remote computer; or a device connected to SCADA system.
 22. The device of claim 20 wherein the controller uses the animation to detect pump-off conditions on a rod pumped well.
 23. The device of claim 20 wherein the controller uses the animation to control the speed of a drive on the rod pump. 